I have worked with men/offenders who have been ordered by a court not to contact their child directly or indirectly, because of the risk they contine to present to the child. Some children, when they have reached 18, have been helped to obtain injunctions.
It's all very well for the Daily Mail to take up the cause of someone who has 'only' wished his son a Happy Birthday on Facebook, but for many in such a situation, this behaviour rides rough-shod over the needs and safety of that child or young adult.
How intimidating for this young man, to receive a message that tells him 'you are still within my reach and my power if I choose to contact you despite being legally prevented.' This order wasn't imposed on a whim. Men who have posed a threat to their children, and use subtle ways to tell them they can get at them, can strike terror with such behaviour without anyone else understanding the harm they are perpetrating.